Hypoxemia: Definition, Causes, and Treatment

Definition of hypoxemia

Hypoxemia (also known as
low oxygen desaturation) is defined as an abnormally-low partial
pressure of oxygen in the arterial blood. Oxygen cascade (or oxygen delivery
from the outer air to body cells) is highly sensitive to various
abnormalities that can appear anywhere in the air (e.g.,
reduced oxygen content), airways, lungs, or cardiovascular
system. The examples and causes are explained below. Oximeters
are commonly used these days in hospitals and by critical-care
professionals to define blood oxygen levels and diagnose hypoxemia.

On an average, the normal oxygen levels in our bloodstream are about 85
mm Hg. In people suffering from hypoxemia, this falls down to as low as 60
mmHg. During hypoxemia, the oxygen saturation in the body is less than 90
percent. This is the formal definition of hypoxemia. Normal pulse oximeter
readings can range from 95 to 100 percent. If the same falls below 80
percent, the condition is referred to as severe hypoxemia.

Causes of hypoxemia

1) The
inspired air has reduced oxygen content (e.g., at high altitude or
due to other causes).

2) Insufficient gas exchange is caused by alveolar hypoventilation (or
breathing too little) with chest breathing. It can happen, for example, during sleep
or during physical exercise for people with lung diseases.

3) Some parts of the lungs are obstructed, or damaged, or have
insufficient ventilation (e.g., as for emphysema, COPD and other
conditions).

4) Blood shunting causes the arterial and venous blood to mix and this
causes reduced oxygenation of the arterial blood.

5) Impaired alveolar-capillary diffusion (e.g., due to thick mucus during
exercise in people with cystic fibrosis).

The main cause of chronic hypoxemia

While
hypoxemia may occur suddenly, or due to an accident or unusual and
exotic situations, most cases of chronic hypoxemia relate to gradual
worsening of blood oxygenation due to chronic lung diseases, such as cystic
fibrosis, COPD (severe asthma, bronchitis, emphysema, and so on), lung
cancers, bronchiectasis and many others. In such cases, gradual
deterioration in blood oxygenation is accompanied by hypercapnia (too much CO2
in the arterial blood) and has a simple single cause: an abnormal
breathing pattern that is manifested in the following factors:
- hyperventilation
- thoracic (or chest, or shallow)
breathing
- mouth breathing.

Hyperventilation, regardless of the ventilation-perfusion ratio (or the
presence of lung problems during the initial stages), leads to alveolar
hypocapnia. This, in turn, causes a cascade of pathological effects that involve
drying and overcooling of airways, constriction of airways, inability of the
body to heal lung damage, over-production of thick mucus, suppression of the
immune system, possible appearance of allergies, over-expression of
hypoxia-inducible factor 1, oxidative stress, and many other effects (see the
CO2-related links below). Alveolar hyperventilation leads to the appearance of 2
other factors: chest breathing and mouth breathing.

Chest breathing immediately leads to reduced-blood oxygenation
since lower portions of the lungs get about 6-7 times more blood, due to
gravity, in comparison with the top parts of the lungs.

For uneducated and archaic views on hypoxemia, you may check this
Wikipedia article: click
here.

Treatment for hypoxemia

Note. Severe cases of hypoxemia require the attention of emergency or
critical care professionals. Their treatment for hypoxemia may include
mechanical ventilation and supplemental oxygen therapy.

Successful treatment of chronic hypoxemia in patients with COPD, cystic
fibrosis, emphysema, severe asthma, and other lung diseases has been
demonstrated clinically by more than 600 Russian MDs. This website provides detailed instructions for Buteyko breathing exercises. However, after testing my students, I know that there are even better methods that work nearly twice more effectively. The names of these methods are provided below down here as your bonus content.

One also needs to address lifestyle-risk factors (supine sleep, mouth
breathing, overeating, insufficient or incorrect physical exercise,
nutritional deficiencies, and many others) in order to achieve permanent
changes in automatic breathing patterns. These factors are analyzed in the
Section Learn here.